I can't see anything that should stop them. Your file validates in Brett's robots.txt validator [searchengineworld.com]. The only thing might be to insert a space between the # and actual comment, not sure how nitpicky some spiders are, but that's the format used at robotstxt.org.
There doesn't look to be anything on your index page to stop them going further. You might try putting up a fresh link or two on the page and see if they follow those.
A service I was trying to use for my site-level search (not G, as I can't get them to re-index whenever I want) explained my problem.
"I took a look at your account and I noticed that your page has links such as [MyDomain.com...] Because there is a slash missing from the end to make the URL [MyDomain.com...] the spider receiveds a re-direct to [MyDomain.com...] but cannot follow the re-direct. "
That was the case for one spider, at least ... possibly more.
Hope this helps somebody else -- and thanks to those who gave me some ideas earlier.